Gun cartridge



' 'WILLIAM A. CABUTH, OF LOS ANGELES, CALIFORNIA.

PATENTv OFFICE.

GUN CARTRIDGE.

Application led September 22, 1926. Serial No. 136,984.

My invention relates generally to gun cartridges and more particularlyto that class of metallic and paper cartrid es that have a powderchamber of enlarged iameter as compared to the diameter of theprojectile and bore of the gun. Y

In the operations incident to the manufacture of the shell component orcase in high power small arms ammunition the requirements call for thecontraction or crushing down of the straight drawn metallic cai'- tridgeshell, thus producing a tapered Shoulder near the forward end of theshell and forming a neck of reduced caliber to receive and hold theprojectile. This crushing or contraction process, carried out for thepurpose of producing at the forward end of the cartridge shell ashoulder and a neck of reduced diameter, causes inherent weaknesses atboth the taper andneck of the shell and further the operations incidentto the reduction of diameter or bottle necking of the shell addmaterially to production costs.

My invention has six principal objects:

First, the production of a cartridge with an explosive containingchamber of superdiameter as compared to the caliber of the projectileand bore of the gun, together with the elimination of the shoulder andneck at the forward end or mouth of the shell.

Second, the provision of a'cartridge shell having exterior and interiorwall surfaces following a modified taper, or if specifications require,with straight cylindrical eX- terior and interior wall surfaces, saidshell having an explosive chamber of superdiameter, thus contributing tostrength at the nozzle or mouth of the shell and enablin the shells orcartridges to' be readily pro uced and with minimum cost of manufacture.

Third, the accomplishment of an automatic obturator or gas. check by theprojectile due to the shape of the rear portion thereof, whereby at therst instant of explosion, the escape of powder gas between the cartridgeshell and the rojectile is stopped. This action material y increases theeiiiciencyof the combustible charge by preventing escape of power, andsuch action also protects the bore of the gun from erosion caused by theusual swift passage of superheated gas around and in front of theprojectile before the same has moved' forwardly into and completelyiilled the bore diameter of the gun. F ourth` the elimination of loss ofpower and accuracy in the case of fire arms that have been boredirregularly or above the usual limits of the maximum tolerance that isallowed over standard bore diameters. This is obtained by having myimproved projectile made in two diameters, the diameter of the forwardor reduced portion of the projectile conforming to the standard bore andrifling of the gun and the diameter of the larger rear portion of theprojectile being that of the outer rim of a hollow cup that movesforward and contracts and shapes itself into the reduced actual borediameter during the iirst instant of combustion of the explosive charge.

Fifth, the`provision of a suitable stop or check to restrain thecartridge from moving too far forwardly into the breech or chamber ofthe gun while being inserted thereinto, said stop or check also servingto support the cartridge shell against the forward thrust of the firingpin at the time of discharge. This stop or check, which is to hold thecartridge in proper place within the chamber or breech of the gun, is inthe form of a shoulder, preferably tapered so that its diametergradually increases toward the rear of the body of the projectile. Thus,my improved cartridge does not require as a chamber stop the heretoforegenerally used rim or semi-rim that projects from the base of the shell,nor does it require the commonly designed stop shoulder in the bottleneck of the rimless cartridge case.

Sixth, the reduction of recoil and the lessening of gun barrel strainsand vibrations by the elimination of all changes and irregularities ofgas pressure and projectile velocity while the projectile is passmgthrough the bore of the gun.

With the foregoing anad other objects in view, my invention consists incertain novel features of construction and arrangement of parts thatwill be hereinafter more fully described and claimed and illustrated inthe accompanying drawings in which:

Fig. 1 is an elevational View of a cartridge constructed in accordancewith my invention.

Fig. 2 is a longitudinalsection taken on a plane through the center ofmy improved cartridge. y

Fig. 3 is a sectional View ofa cartridge embodying the rinci les of myinvention and which includes a boat tail projectile.

Fig. 4 is a sectional view showing the forward portion of the shell orcase with the projectile therein,4 said parts being shown positionedwithin4 a gun barrel and with dotted lines showing the contractedposition of the rear portion ofthe projectile as the saine passesthrough the bore of the Fig. 5 is .aA` longitudinal' section takenthrough the center of a cartridge of my improved construction and withthe rear end of the shell or case provided with a projecting rim. j

Fig. 6 is a longitudinal section through the center of a shel'lconstructed'in accordance with my invention and which is vparticularlyadapted for automatic riiles, machine guns, self-loading rifles, and thelike.

Fig. 7 is a longitudinal section taken through the center of a cartridgeconstructed in accordance with my invention and which is suitable foruse in automatic pistols and sub-machine guns.

Referring b letters to the accompanying drawings, an particularly to theform of cartridge illustrated in Figs. 1 and 2, A designates theprojectile, S th-e cartridge she'll or case,T the tapered shoulder onthe projectile, E the cannelure or groove for the accommodation Aof theshell extractor and X the circumferential line betweenthe rear end ofthe tapered shoulder T and the .front end of the portion of theprojectile that has the greatest diameter, which portion of `greatestdiameter is positioned in the forward ortion of the shell or case sothat the line between said portion of greatest diameter and the rear endof the tapered shoulder T practically coincides with the straightshoulder' at the forwardend of the wall of the shell or case S.

Projectile A is made up of a jacket .or relatively hard metal havinggreat ductility and a core of lead or analogous metal and which core isprovided in its base or rear portion with a substantially conical recessM and the inner end or bottom of .said recess is made substantiallyv atso as to provide a pressure face Y. Jacket J wholly encloses theenlarged base or rear portion of the projectile and the `rear .edge ofsaid jacket is preferably lianged. inwardly over the endl of the wall ofcore G that surrounds chamber M, as designated by F.

When the projectile is roperly seated'in the shell or case S, the camber M within the hollow base of the core 'C provides a forwardextension for the loading space within the shell S that receives thecombustible charge. Seated -in the base orv rear end of the shell S isthe usual primer and fulminate P. I

vIn Fig. 3 I have illustrated a projectile of the type generallydescribed a s a. boat tail and where this form of projectile embodies myinvention, the rear portion of the core C of the projectile terminatesin a v boat tail portion C1 that is enclosed by a jacket J1L and thisjacketed boat tail portion is concentrically arranged within thatportion of the projectile jacket J that is Iseated in the mouth orforwardend of the shell S, there being an annular space between tlierear portion of jacket J and the boat tail portion of the projectile..

In Fig. 4., L designates the loading space 'for the combustible charge,S the shell orportion of the bore B in this yligure illus? trate theform assumed by the bas-e'portion of the projectile after it hasreceived the first impulseof forces resulting from combustion of thecharge and when said projectiley has been moved forwardly into the boreof the gun. Inasmuch as the recessed base of the projectile is collapsedwhen said projectile enters the bore of 'the gun, the recess M will bematerially reducedV in diaineter and it will take substantially the formas indicated by dotted lines H.

-In Fig. 5, I have illustrated a cartridge provided at its baseer rearend with a rim or iange, but as a result of my invention of a. dualcaliber projectile, or a projectile having an enlarged hollow base, theshell has a superdiameter explosive chamber without resorting to theusual bottle neck in the forward portion of the shell. The case or shellS illustrated in this gure is uniformly tapered throughout its entirelength, v

It is obvious that it is one of the purposes of my invention to precludethe necessity of fa rimmed cartridge shell such as Fig. 5 portrays, butthis design is to show the possibility of the use of a projectile of myinvention ina cartridge suitable for use without sub-alteration of thechamber in a firearm constructed for handling cartridges with shellshaving rimmed heads.

The form of cartridgeillustrated in Fig. 6 is especially adapted for usein automatic rifles, machine guns and self-loading ries of the so-calledblow back type. In this y instance, the case or shell has the sameexternal diameter throughout ,its length and the formation of a semi-rimor stop behind the extraction cannelure at'thebase of the cartridge is.avoided by the provision ofthe tapered shoulder T 0n the intermediatepory tion of the projectile. A

In Fig. 7, I have illustrated a cartridge particularly designed for usein automatic pistols and sub-machine guns. This particular cartridge isvey similar to the structure illustrated in ig. 6 in'. that thecartridge case is of uniform external diameter throughout its length andthe tapered shoulder T on the projectile obviates the necessity for asemi-rim at the shell or case.

Thus it will be seen that my invention contemplates a cartridge shell orcase consisting of a straight drawn metallicor paper casing having asuitable head or base, the latter being cannelured or rimmed forextraction and carrying the usual primer, the chamber within the shellor case being adapted to receive the explosive charge and said shell orease holding at its forward ehd a projectile having two differentdiameters, the portion of greatest diameter being seated in the shell,there being a tapered shoulder between the' two portions of theprojectile of different diameters and the enlarged base of theprojectile being recessed.

Drawing is one of the least expensive forms of metal working and byeliminating the bottle neck and the turned semi-rim, manufacturingoperatins involving VcomponentY weaknesses and. excessive costs areavoided. The shell per'se herein described include nothing new ororiginal and no claim is made thereto, except as combined with aprojectile of the particular construction herein described andillustrated.

My invention has been described as relating to certain forms of riflecartridges and pistol ammunition, but it should be understood that myinvention is applicable to cartridges for all arms and ordnance usingfixed and complete unit ammunition. It is generally known and understoodthat the term fixed and complete unit ammunition herein referred todescribes ammunition in which the primer or fulminate is placed in thebase of the cartridge case, the explosive charge occupying 'the greaterportion of the chamber within the cartridge case and the projectile orlethal load being carried in the forward portion of the shell or case orVseated therein and projecting forwardly therefrom, all of the part justmentioned being firmly joined together and a. fixed and complete unit ofhandling an loading for each discharge of the gun.

The projectile contemplated by mj; invention may be properly describedas eing of dual caliber inasmuch as it is formed with two differentexternal diameters, the portion of smaller diameter being arranged infront and conforming with the caliber of the bore or rifling of the gun.The rear portion of the projectile has the greater diameter and thisportion is fitted into the forward portion or mouth of the shell 0rcasing. The projectile may be swaged into the shell by pressure orcrimped therein. The tapered portion of the projectile that connects theportions of different diameters provides a shoulder and stop for thecarbase of the cartridge providintridge when the latter is positioned inthe breech or chamber of the gun and likewise furnishes support when thefiring pin strikes the primer to lire the cartridge.

It is obvious that if the forward edge or rim of the shell be ofsufficient thickness to abut against a corresponding shoulder in the gunbarrel it will assist the shoulder in the projectile in sustaining theforward thrust of loading and firing, but where the cartridge casef orshell is of thin metal this assistance would be insuflicient to functionip slllipport of the forward thrust against the s 1e The enlarged baseand tapered portion of the projectile are provided with a centrally orconcentrically arranged recess or chamber which, it will be readilyunderstood, permits the enlarged krear portion of the projectile tocontractorr crush inwardly as the projectile enters and passes throughthe bore of the gun.

Sub-caliber orcontracted diameter. projectiles with hollow -or recessedbases have been long known and used and Imake no claim for the inventionof a hollow base pro-` jectile recessed or cupped out within a portionof its rea-r body where the outer diam eter is vless or no greater thanthe bore of the gun.

The phrase super-caliber used herein refers to the commonly constructedcartridgeY with an enlarged diameter powderchamber. My inventioncomprehends a cartridge containinga projectile having a hollow rearportion or base with an outer diameter substantially greater than thatof the front p0rtion of said projectile and which front portion conformsto the bore of the gun. .My invention further includes a cartridgecontaining a projectile having an enlarged rear portion, the diameter ofwhich is substantially greater than that of the bore of the gun,the-forward lportion of said enlarged rear end having a tapered exteriorsurface, said enlarged and tapered yrear portion being cupped orrecessed so that it will contract as it enters the bore of t-he gun, andwhich bore is smaller in diameter than the diameterV of the recessedenlarged rear pol'- tion of said projectile. The recess that is formedin the base or rear portion of the projectile must be large enough tostill remain when the larger rear portion of the projectile is collapsedor compressed when it enters and passes through the caliber diameter of-the bore, and in order that this result may be attained, the recess ispreferably tapered toward its forward end and of necessity it mustextend forwardly until its forward end or the surface Y is practicallycoincident with or a slight distance forward of the forward end of thetapered shoulder T. In

vother words the recess or cavity extends ena recess or cavity' lOl lll

ltirely through the rear portion of thevlargest diameter and throughthat portion of j the projectile body encompassed by the excaliber solidbodies, but only the slightest and almost inconsidcrable increase indiameter can be accomplished therebyl owing to the tremendous increasein4 breech pressures involved. My invention, by the use of a projectilewith a body of super-diameter in its Arear and recessed within saidsuper-diameter, insures the contraction of a vbase of materiallyenlarged outerA diameter without undue pressures'being incurred. f

A further decided advantage `arisingf'ron'ly my invention is theprevention of practcally all gas escape between theshell and pro-,jectile during the first instantof combustion o'f the explosivecharge,.for as the projectile is forced from the mouth of vtheshell, aperfect seal is effectedv between the enlarged base portion of theprojectile as it passes the.

tapered shoulder -within the gun bore against which the tapered portionT of the projectile normally rests. The high 'speed rush and wash of gaspreceding the projectile ,through the lead and bore is impossible andthus thefull power of the eXplo.. sive charge is conserved. Y v

Another advantage of my invention arises from the fact that the modifiedtaperedor straight cartridge'shells that receive the dual caliberprojectiles will not stretch with high .pressure loads-and said shellsmay be ,readily resized as to diameter for reloading,

whereas the shells of the bottle neck type of cartridge'when used withhigh intensity charges, become lcngthened and cannot be successfullyrecharged and used again. The bottle 4neckslicll also requires morecareful metallurgical selections and testing than does thestraightshell, and in times of large and urgent quantity manufacture, the bottleneck cartridgeis always al product -of doubtful and uncertain quality.

A further advantage that prevails in fixed ammunition by the :use of myinventionj is the tapered recess or chamber in., the rear or base Vofthe projectile for, by referring to Fig. 4 it willl be seen that theprojectile has full bore diameter at thepoint designated .by the dottedline Y and to the rear of this.,

line as the projectile moves forward into u the gun bore the pressure ofgases within the contracted recess holds the cupped and tapered rear'portion of the projectile firmly against the rifling andv maintainscomplete contact with'the bore of the gun. .The Hextheshell and therelatively simple stamping `or diel process forshaping the projectile,to-

gether with the'usual assembly of the component parts of the cartridge,so that all complex operations requiring special gauging and inspectionare avoided. l

A further advantage obtained by the'use ,of a cartridge with aprojectile of my invention,.is lthat gas pressures within the bore ofthe gun are regulated more evenly than 1s the case with theordinarycartridge having a projectile lot' the usual shape and form. With' theconnnonly'designed cartridge, at the instant of -vlirst ignition of thecombus tion charge, the projectile at zero breech pressure leaps out ofthe mouth of the cartridge shell and travels in the small bore rifle adistance of approximately two inches before. shaping itself into theboreat a point,

of maximum pressure and low velocity. From this point forward,y the fullimpetus ofniaximum pressure having been received, the projectile travelstoward the muzzle of the gun with a constantly decreasing pressure andwith a constantly increasing vclocity.

lt is an axiom among authorities on inter- Vnal ballistics that highpressure on tliep'art of the gases fromthe combustion at a point withinthe bore', means low velocity on thev part of the projectile at saidpoint, and vice versa. A. rising curve of gas pressure, means adecreasing velocity for the projectile, and

a falling curve of gas pressure,'1neans an increasing velocity for theprojectile.

By my invention the full height of the pressure curve,4 calculatedwithin the bore during the firing of the cartridge is developed by theexplosion and expansion of the combustion charge at a point-nearer the`breech and at least two inches farther back -toward the chamber of thepiece than is usual. Thereforemy invention by forcing,

at the first instant of discharge a reduction in diameter andacontraction of, the rearward hollow super-caliber section of t-heprojectile retards the customary sudden leap of the projectile into thebore, and avoids the subsequent slowing downof the projectile velocityata point of high pressure materially forward in advance vof thecartridge chamber.V j

My invention hence', provides for the cartridge, a projectile thatdevelops anl immediately substantially highpressurev withI low velocityat its iirst'advance lup the bore; and

there -is no primary increase, intermediate lsof forwardly throughdecrease and final increase in the velocity of the projectile, butinstead only a regular increase of the velocity accompanied by aconstantly reduccd'pressure curve as the projectile approaches themuzzle of the y invent-ion, therefore, by eliminating velocity changesYithin the bore during the discharge of the cartridge, produces areduction and an evenncss ofrecoil and" relieves unnecessary strains andvibrations within the gun barrel. l

While I have herein illustrated and described the projectile as beingcomposed of :t lead core and ductile jacket, it will be understood thatmy invention comprehends a projectile composed -`wholly of lead, leadalloy, or any other suitable metal or combination of metals.

Itwill be understood that minor 'changes in the size, form andconstruction of the various parts of my improved cartridge may be madeand substituted for those herein shown and described without-departingvfrom the spirit of the invention, the scope of which is set forth inthe appended claims.

I claim as my invention: 1. A cartridge comprising a shell having a.super-caliber chamber adapted to receive an explosive charge, aprojectile having two diferent diameters, the forward portion of whichprojectile, and which has the smaller diameter being adapted to enterthe bore of a gun, the rear portion of theprojectile and which has lthelarger diameter being seated in the mouth of the super-caliber explosive`Achamber within lthe cartridge shell the portions of different diameter'of said projectile being joined by a tapered shoulder and the largerrear portion of said projectile being provided with a tapered recessthat extends the shouldered portion of the body of sald projectile tothe caliber diameter thereof.

2. A cartridge comprising a shell and a projectile having two thesmaller diameter being adapted to enter the bore of a gun, the rearportion of greater diameter of Said projectile fitting snugly within theforward portion of the super-caliber explosivechamber in the shell, theportions ferent 'diameters beir'igV joined by a tapered shoulder that isadapted to bear against a shoulder within the cartridge chamber of thegun in which the cartridge is positioned, and the larger rear portion ofsaid projectile being provided with a tapered recess that extendsforwardly through the shouldered portion of the body of said projectileto the caliber diameter thereof.

3. A cartridge comprising a shell and a projectile having two differentdiameters, the forward portion of said projectile having the smallerdiameter being adapted to enter piece. i

, tridge is different diameters,` e forward portion of said projectilehaving recess that i-s open to the of said projectile having difthebore'of a gun, the rear portion of greatcaliber explosive chamber in theshell,'the portions of said projectile having different diameters beingjoined by a tapered shoulder that is adapted to bear against a shoulderwithin thc carl ridge chamber of the gun in which thecarlridgc ispositioned so as to function as a stop to support the cartridge inproper position against the forward thrust of thc bolt in loading andthe forward blow of the tiring pin at the time of' discharge and thclarger rear portion of said projectile being provided with a taperedrecessl that extends forwardly through the shouldered portion of thebody of said projectile .to the caliber diameter thereof.

4.- A cartridge comprising a shell, -a projcctile having two differentdiameters, the portion of said projectile having the greatest diameterbeing seated in the forward portion of the shell. the portion of lea-stdiameter of said projectile being adapted to enter the bore of the gunin which the carpositioned, the portions of different diameter of saidprojectile being connected in front of and outside the shell by atapered shoulder that is adapted to bear yagainst a diameter thereof.

5. A cartridge comprising a shell, a projectile having the forwardportion of its body reduced in diameter so as to conform to the bore ofthe gun in which the eartrldge is fired, the rear portion of the body ofthe projectile having greater diameter than the forward portion.'theportions of different diameters being joined by a tapered shoulder andthe enlarged rear portion of said projectile being formed with acentrally arranged rear of the body of the projectile and which extendsforwardly through that portion of thebody that is encompassed by thetapered shoulder.

6. A cartridge comprising a shell, a projectile having the forwardportion of its body reducedin diameter so as to conform to the bore ofthe gun in which the cartridge is tired. the rear portion of the body ofthe projectile having greater diameter than the forward portion, theportions of different diameters being joined by a tapered shoulder andthe enlargedl rear portion of said projectile being formed with aconeentrically arranged chamber that is open tothe rear of the body ofthe projectile and which extends forwardly through Vthat portion of thebody that is' encompassed by the tapered shoulder.

7. A cartridge comprising a shell having an external Wall of straightcylindrical form throughout its length, a projectile having a body oftwo diameters` the front portion of the internal diameter of the frontportion of the super-caliber explosive chamber within the cartridgeshell and the chamber Within the hollow segmental rear portion of thebody extending forwardly to the transverse plane occupied by the rearportion of the projectile body that conforms to the bore of the gun. l

8. A cartridge comprising a shell, a projectile seated in the forwardportion of said shell said projectile having an externally arrangedtapered' shoulder intermediate its ends, so that the forward portion ofsaid projectile is smaller in diameter than the rear portion, and thelarger rear portion of said projectile being provided with a forwardlyextending tapered recess that extends through that portion of the bodyof the projectile that is encompassed by the tapered shoulder.

9. A cartridge comprising a shell, a projectile seated in the forwardportion of said shell said projectile having an externally ,arrangedtapered shoulder intermediate its ends` so that the forward portionofsaid projectile is smaller in diameter thanlhe rear portion, thelarger rear portion lof said projectile being provided lwith a forwardlyextending tapered recess that extends through that portion of the bodyof the projet-tile that is encompassed by the tapered shoulder, and theforward vend of which recess terminates in a flat pressure receivingface. j l

In testimony whereof I affix my signature.

WILLIAM A. CARUTH- j

